# Sum of Infinite Geometric Sequence/Corollary 2/Mistake

geometric series

## Mistake

The sum of the finite initial segments of the series is:
$\dfrac {a \paren {r^n - 1} } {r - 1}$,
whence, if the infinite series converges, its sum is $a / \paren {r - 1}$.

## Correction

whence, if the infinite series converges, its sum is $a / \paren {1 - r}$.